Fancy a family hatchback that can cruise comfortably all day at twice the national speed limit if it were allowed to? Then think about a Vectra diesel.

Not the most obvious choice, perhaps, but with a three-litre V6 engine beneath its bonnet, the flagship diesel Vectra is a formidable machine.

It also comes in estate form and although the saloon model makes do with the less powerful 1.9-litre four cylinder engine, it is still is capable of hitting 135mph.

When an engine is as big as the three-litre V6 of the Vectra it is not so much about power as torque. This is the pulling power that enables suitably endowed cars to haul horse boxes and the like with ease.

In the case of the Vectra the torque figure is 273lb/ft, which is a lot. When used to pull the car only it results in a 0-62mph acceleration time of just over eight seconds, which is good but not exceptional. A Mercedes C-Class with a 3.2-litre diesel engine can cover the same distance in just 6.9 seconds and has a top speed of 12mph more than the Vauxhall at 155mph.

However, while the most expensive Vectra diesel costs just under £25,000 the equivalent Merc is more than £30,000.

Mercedes owners would point the C-Class will retain 53 per cent of its value over three years in comparison to 43 per cent for the Vauxhall.

The SRi version of the Vectra diesel costs £21,645 and is a better long-term bet for those prepared to forgo leather because it has the same residual value as the more expensive Elite model.

However, in either guise a 3.0 V6 Vectra is an expensive luxury when you consider the performance of the 1.9-litre diesel alternative, which is also more economical. The three-litre model should only be considered by those who need its prodigious pulling power or anyone considering second-hand, at which point it becomes a steal.